1. Field of the Invention
The invention relates to a method and arrangement for implanting or explanting an intravascular catheter which reduce friction between the catheter and the blood vessel through which the catheter is being moved.
2. Description of the Prior Art
The introduction of an intravascular catheter, for example a pacemaker electrode, into the body of a patient is impeded by friction between the catheter and the wall of the blood vessels accommodating the catheter. In order to reduce the friction, it is known to coat the electrode catheter with a lubricant.
Within a few months after the implantation, the electrode catheter becomes enclosed by a layer of connective tissue which anchors the electrode catheter in such a way that it is difficult, dangerous or even impossible to withdraw the catheter from the blood vessels accommodating it. Therefore, when an explantation of the catheter is not absolutely necessary it is required to weigh the risks associated with the explantation of the catheter against the risk to the patient in leaving the catheter in his body. If, by contrast, as in the case of an infection, an explantation of the catheter is absolutely necessary and the risk associated with the withdrawal of the catheter is too large, the withdrawal of the catheter requires the blood vessels accommodating it to be cut open.
An intravascular catheter is disclosed in U.S. Pat. No. 4,749,376 which has a tool at its distal end for removing deposits in blood vessels or for widening vasoconstrictions. Arranged at the proximal end of this known catheter is a motor whose rotary movement is transmitted by a control wire e interior of the catheter to the distal end thereof and is converted into an oscillating stroke of the tool in the direction of the longitudinal extent of the catheter.
Another intravascular catheter disclosed in U.S. Pat. No. 3,352,303, having an electromechanical transducer disposed at a proximal end of the catheter whose vibrational energy is transmitted, for example, via a wire or a liquid to the distal end of the catheter for the purpose of breaking up intravascular blood clots.
A similar catheter for removing vessel blockages is disclosed in U.S. Pat. No. 4,854,325, in which a control wire extends through the catheter and projects from the distal end of the catheter, and is set into an oscillating stroke by a motor at the proximal end of the catheter.
A common feature of these known catheters is that in each case, a stroke is generated at their distal end in the direction of the longitudinal extent of the catheter, so that obstructions in the path of introduction of the catheter can be removed. In these known catheters the friction between the catheter and the wall of the blood vessels accommodating the catheter is not reduced by the strokes. Moreover, in these known catheters there is the risk that the wall of the blood vessel accommodating the respective catheter will be pierced by the distal catheter tip. Finally, the above-named catheters are not provided for longer term implantation in the human body, so that the initially cited problems do not occur in connection with the explantation of the catheter.